Aircraft with movable wing tip device

ABSTRACT

An aircraft is disclosed having a device and an aircraft wing. The aircraft wing includes a main wing element and a movable wing tip device attached to a tip end of the main wing element. The movable wing tip device includes an accumulator configured to store energy and the movable wing tip device can move relative to the main wing element to vary a span of the aircraft wing. The accumulator is configured to transmit power to the device. The accumulator enables energy to trickle between the main wing element and the movable wing tip device whilst still providing a suitable power source to the device. Additional embodiments include a method of maintenance, and a method of operating the aircraft wing to store energy in the movable wing tip device.

FIELD OF THE INVENTION

The present invention relates to an aircraft, an aircraft wing and amovable wing tip device.

BACKGROUND OF THE INVENTION

Developments in commercial aircraft have resulted in larger aircraftwith higher performance efficiency, for which it is desirable to havecorrespondingly large wing spans. However, the maximum aircraft wingspan is effectively limited by airport operating rules which governvarious clearances required when manoeuvring around an airport. Toalleviate this problem, it is known to provide aircraft with wingshaving a foldable portion. In the ground configuration, the foldableportion is moved by, for example, rotation relative to the main body ofthe wing, such that the overall span of the wing is reduced. Thus, theaircraft can comply with airport operating rules, yet benefit from thelarger span in flight. Foldable wings may also be provided on militaryaircraft to allow aircraft to be stored where space is at a premium,such as on aircraft carriers.

Aircraft may be required to have components in the wings such as, flaps,ailerons, spoilers, lighting arrangements, and other devices whichconsume power or require control data. It is desirable to communicatedata and/or power between the aircraft's wing tips and the main bodyelement of the wing especially in flight. Such components in the wingare not necessarily required when an aircraft is not in flight.

If such components are provided in the movable wing tip device, then aproblem which may be encountered is that electrical wiring may need tobe provided from the aircraft power system to the movable wing tipdevice across a joint where the wing is arranged to fold. In service,such wings may move from a retracted to a deployed position severaltimes a day, leading to wear and tear of the wiring and its associatedconnectors/contacts such that the connection system needs to befrequently maintained.

SUMMARY OF THE INVENTION

A first aspect of the invention provides an aircraft comprising anenergy consumer and an aircraft wing. The aircraft wing comprising amain wing element and a movable wing tip device attached to a tip end ofthe main wing element. The movable wing tip device can move relative tothe main wing element to vary a span of the aircraft wing. The movablewing tip device comprises an accumulator configured to accumulate energyand output the energy to the energy consumer.

The movable wing tip device can comprise the energy consumer.

The accumulator can be configured to receive the energy from the mainwing element.

The movable wing tip device can comprise the energy consumer. Theaccumulator can be configured to receive the energy from the main wingelement.

The aircraft can comprise one or more inductive couplers arranged totransmit the energy from the main wing element to the accumulator.Alternatively, or in addition, the aircraft can comprise one or moreinput wires arranged to transmit the energy from the main wing elementto the accumulator.

The energy consumer can comprise an actuator. The actuator can be a wingtip actuator configured to move the movable wing tip device relative tothe main wing element to vary the span of the aircraft wing. Theactuator can be a control surface actuator.

The aircraft can comprise a power source configured to transmit theenergy to the accumulator. The energy consumer can be configured toconsume the energy from the accumulator at a higher power level than thepower source is configured to transmit to the accumulator.

The accumulator can comprise at least one of a super capacitor, abattery, a flywheel, and a hydrogen fuel cell with a hydrogen tank.

The aircraft can comprise one or more input wires and one or more outputwires connected to the accumulator. The accumulator can be configured toreceive electrical energy via the one or more input wires and outputelectrical energy to the energy consumer via the one or more outputwires, each input wire is rated to a first current level, each outputwire is rated to a second current level, and the first current level islower than the second current level.

The accumulator can comprise a hydraulic accumulator configured tooutput hydraulic power to the energy consumer. Alternatively, theaccumulator can comprise a pneumatic accumulator configured to outputpneumatic power to the energy consumer.

The movable wing tip device can have an inboard end and an outboard end.A centre of gravity of the accumulator can be closer to the inboard endthan it is to the outboard end.

The movable wing tip device can comprise an access area with a removablecover. The accumulator can be fitted in the access area.

The movable wing tip device can comprise a front spar and a rear spar.The accumulator can be between the front spar and the rear spar. Themovable wing tip device can be attached to the tip end of the main wingelement by a hinge.

The accumulator can be configured to store more than 0.02 kWh, 0.1 kWhor 0.5 kWh.

A second aspect of the invention provides an aircraft wing comprising amain wing element and a movable wing tip device attached to a tip end ofthe main wing element. The movable wing tip device comprising an energyconsumer and an accumulator. The movable wing tip device can moverelative to the main wing element to vary a span of the aircraft wing,and the accumulator is configured to receive energy from the main wingelement, accumulate the energy, and output the energy to the energyconsumer.

A third aspect of the invention provides a movable wing tip devicecomprising an accumulator configured to accumulate energy and output theenergy to an energy consumer. The movable wing tip device can furthercomprise a hinge lug for attaching the movable wing tip device to a tipend of a main wing element.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to theaccompanying drawings, in which:

FIG. 1 a shows a front view of an aircraft incorporating a wingconstructed according to the invention with the movable wing tip devicein a deployed position;

FIG. 1 b shows a front view of the aircraft of FIG. 1 a with the movablewing tip device in a retracted position;

FIG. 2 a shows an isometric view of a portion of an aircraft wingconstructed according to a first embodiment of the invention with themovable wing tip device in the deployed position;

FIG. 2 b shows a rear sectional view of the inductive coupler in aportion of the wing of FIGS. 1 a, 1 b, and 2 a with the movable wing tipdevice in the deployed position;

FIG. 3 a shows an isometric view of a portion of the wing of FIGS. 1 a,1 b, 2 a, 2 b with the movable wing tip device in the retractedposition;

FIG. 3 b shows a rear sectional view of the inductive coupler in aportion of the wing of FIG. 3 a with the movable wing tip device in theretracted position;

FIG. 4 shows an isometric view of a portion of a wing constructedaccording to a second embodiment of the invention with a movable wingtip device in the deployed position;

FIG. 5 shows an isometric view of a portion of a wing constructedaccording to a third embodiment of the invention with a movable wing tipdevice in the deployed position;

FIG. 6 shows a sectional view of a hinge comprising a base and a remoteof an inductive coupler;

FIG. 7 a shows a planform view of a multi-spar movable wing tip deviceshowing possible accumulator positions;

FIG. 7 b shows a planform view of a multi-rib movable wing tip deviceshowing possible accumulator positions; and

FIG. 8 shows an isometric view of a portion of a wing constructedaccording to a further embodiment of the invention with a movable wingtip device in the deployed position.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Like reference numerals refer to like parts throughout thespecification. With reference to FIGS. 1 a and 1 b, a passenger aircraft1 is shown. The aircraft 1 comprises a fuselage 2 for holding passengersand/or cargo, a starboard wing 3 and a port wing 4. Each of the wings 3,4 comprises a main wing element 5 and a movable wing tip device 6 at thedistal end of the wing. The aircraft 1 is shown in an in-flightconfiguration in FIG. 1 a. In FIG. 1 b, the aircraft 1 has its landinggear 7 lowered and is shown in an on-ground configuration, as whentaxiing at an airport.

With reference to FIGS. 1 a, 1 b, and 2 a the main wing element 5 of thewing 3 extends outwardly from the side of the fuselage 2, with themovable wing tip device 6 movably mounted to a tip end of the main wingelement 5 by a joint which includes a hinge with a hinge line 8. Thehinge line 8 is generally horizontal and aligned in a fore-aft directionparallel with a centre line of the aircraft. This enables rotation ofthe movable wing tip device 6 with respect to the main wing element 5 ina vertical plane as shown in FIG. 1 b. The movable wing tip device 6 maybe electro-mechanically or hydraulically actuated by a wing tip actuatorto move the movable wing tip device 6 relative to the main wing element5 and thus vary the span of the aircraft wing 3.

An aircraft control system is provided on the aircraft 1 which controlsthe wing tip actuator. The wing tip actuator is configured to rotate themovable wing tip device 6 with respect to the main wing element 5 andthus controls the motion of the movable wing tip device 6 between aretracted or folded position (FIGS. 1 b, 3 a, 3 b), and a deployedposition (FIGS. 1 a, 2 a, 2 b, 4, 5). The movable wing tip device 6 ofeach aircraft wing 3, 4 must be in the deployed position for flight.When the aircraft 1 is taxiing at ground level, the pilot mayselectively activate the wing tip actuator to cause the movable wing tipdevice 6 to rotate about the hinge line 8 and into the retractedposition, so that the aircraft 1 can fit into smaller spaces whilstmaintaining appropriate clearance. There are many suitable means bywhich the movable wing tip device may move between deployed andretracted positions which are known to the skilled person.

The span of the aircraft wing 4 when the movable wing tip device 6 is inthe deployed position is shown in FIG. 1 a by arrow 9 a. The span of theaircraft wing 4 when the movable wing tip device 6 is in the retractedposition is shown in FIG. 1 b by arrow 9 b. It can be seen from thearrows 9 a and 9 b that the movable wing tip device 6 can move relativeto the main wing element 5 to vary the span of the aircraft wings 3, 4.Specifically, the aircraft wing 4 has a smaller span in the retractedposition than in the deployed position (i.e. the length of arrow 9 b isless than the length of arrow 9 a).

The aircraft 1 includes an aircraft power system (not shown) and anaircraft control system (not shown). FIGS. 2 a and 2 b show thestarboard wing 3, and the aircraft port wing 4 may be a mirror versionof the starboard wing 3. Each wing 3,4 includes a first electrical wire10, an inductive coupler 12, an electrical input wire 14, and acomponent 16. The component 16 in this example comprises an accumulator16 a and a device 16 b. The component 16 is configured to receive dataand/or power from the inductive coupler 12 and may further be configuredto transmit data and/or power to the aircraft power system and/or theaircraft control system (or other devices) via the inductive coupler 12.

The inductive coupler 12 is arranged to transmit data and/or powerbetween the main wing element 5 and the movable wing tip device 6, byinductive transmission. Inductive transmission (also known as magneticinduction transmission or magnetic induction communication) is theexchanging of an electromagnetic signal (i.e. data and/or power)wirelessly via a magnetic field. The aircraft power system may transmitand receive power to/from the inductive coupler. Similarly the aircraftcontrol system may transmit and/or receive data to/from the inductivecoupler. By way of example the data may be actuation controlinstructions, notification information etc.

The use of an inductive coupler 12 to transfer data and/or power overthe joint reduces maintenance requirements when compared toelectrical/hydraulic cables.

The device 16 b may comprise an energy consumer which is energised bythe aircraft power system. In this case, the accumulator 16 a may beconfigured to accumulate energy from the aircraft power system andoutput the energy to the energy consumer 16 b. The device 16 b may be acontrol surface actuator, a lighting arrangement, a wing tip actuatorconfigured to move the movable wing tip device 6 relative to the mainwing element 5 to vary a span of the aircraft wing 3, or any otherenergy consumer (i.e. a device which consumes energy). A control surfaceactuator is an actuator which is configured to actuate a control surfaceof the movable wing tip device 6, such as a flap, slat or aileron. Insome examples, there may be multiple energy consumers (similar ordifferent to device 16 b) energised by the accumulator 16 a and/or theaircraft power system.

In this example the device 16 b is part of the movable wing tip device6, but in other examples the accumulator 16 a may be in the movable wingtip device 6 but the device 16 b located on some other part of theaircraft such as the main wing element 5 or the fuselage 2.

The accumulator 16 a enables energy to trickle between the main wingelement 5 and the movable wing tip device 6 whilst still providing asuitable power source for the device 16 b. The aircraft 1 comprises apower source to transmit power to the accumulator 16 a, and the device16 b is configured to consume more power from the accumulator 16 a thanthe power source is configured to transmit to the accumulator 16 a.Specifically, the device 16 b may be configured to consume more powerthan the inductive coupler 12 is configured to transmit between the mainwing element 5 and the movable wing tip device 6.

The amount of energy stored by the accumulator 16 a will vary, dependingon the requirements of the energy consumer. Typically, the accumulator16 a is configured to store more than 0.02 kWh, 0.1 kWh, or 0.5 kWh.However, the accumulator 16 a can be configured with a storage capacityin the range of 3 kWh to 12 kWh.

The inductive coupler 12 comprises a base 20 a and a remote 20 b. Thebase 20 a is configured to transmit data and/or power to the remote 20b, and the remote 20 b is configured to receive the data and/or power.The remote 20 b may also be configured to transmit data and/or power tothe base 20 a, which in turn is configured to receive the data and/orpower.

The main wing element 5 comprises the base 20 a, which is mounted at thetip end of the main wing element 5. The base 20 a is configured toelectrically couple with the aircraft power system and/or the aircraftcontrol system via the wire 10. The movable wing tip device 6 comprisesthe remote 20 b, which is mounted at the inboard end of the movable wingtip device 6. The remote 20 b is configured to electrically couple withthe component 16 via the input wire 14.

The base 20 a is configured to inductively transmit data and/or power(e.g. from the aircraft power system and/or the aircraft control system)to the remote 20 b. The remote 20 b may be configured to inductivelytransmit data and/or power in the opposite direction (e.g. from thecomponent 16) to the base 20 a. That is, the base 20 a and the remote 20b may be arranged for: one-way transmission or two-way transmission ofdata; and/or, one-way transmission or two-way transmission of power.

When the movable wing tip device 6 of the wing 3 is in the deployedposition (FIGS. 1 a, 2 a, 2 b, 4, 5), the base 20 a is sufficientlyclose to the remote 20 b such that the base 20 a and remote 20 b caninductively transmit data and/or power between the main wing element 5and the movable wing tip device 6. For the base 20 a to be able toinductively transmit to the remote 20 b, the base 20 a must besubstantially aligned with the remote 20 b (i.e. the axes of the coilsof the base 20 a and the remote 20 b must be co-linear with each other)and the base 20 a must be sufficiently close to allow for inductivetransmission of data and/or power (i.e. the base 20 a and the remote 20b must be within inductive proximity to each other).

There is generally a power and/or data demand by the component 16 whenthe aircraft 1 is in flight and the movable wing tip device 6 is in thedeployed position. There is also generally a lack of demand for powerand/data by the component 16 when the aircraft 1 is on the ground andthe movable wing tip device 6 is in the retracted position.Beneficially, the base 20 a and the remote 20 b are arranged toinductively transmit between each other only when there is demand fordata and/or power between the movable wing tip device 6 and the mainwing element 5, i.e. when the movable wing tip device 6 is in thedeployed position. When demand for data and/or power between the movablewing tip device 6 and the main wing element 5 is absent, the base 20 aand the remote 20 b are arranged to not be in inductive communicationwith each other, i.e. when the movable wing tip device 6 is in theretracted position.

FIG. 2 b shows the main wing element 5 and the movable wing tip device 6in a sectional view from the back of the wing 3. The tip end of the mainwing element 5 and the inboard end of the movable wing tip device 6 areattached together at the hinge line 8 by a hinge 18 b. The hinge 18 bcomprises a pair of coupled hinge lugs connected by a hinge pin. Whenthe movable wing tip device 6 is in its deployed position as in FIG. 2 b, then the main wing element 5 and the movable wing tip device 6 arealso coupled together by a lower pair of coupled lugs 18 a.

The lower pair of coupled lugs 18 a can be uncoupled to enable themovable wing tip device 6 to move between the deployed position and theretracted position about the hinge line 8. Thus, the main wing element 5and the movable wing tip device 6 are connected by the hinge 18 b, andthe hinge 18 b is configured to allow the movable wing tip device 6 torotate relative to the main wing element 5 to vary the span of theaircraft wing 3.

Alternatively, the lower pair of coupled lugs 18 a can be configured asa hinge which enables the movable wing tip device 6 to rotate down intoa downturned retracted position. In this case, the hinge lugs of thehinge 18 b can be uncoupled to enable the movable wing tip device 6 torotate down about the lower pair of coupled lugs 18 a.

The movable wing tip device 6 may be manufactured as a stand-aloneproduct, incorporating the component 16, and optionally incorporatingthe remote 20 b of the inductive coupler. The movable wing tip device 6can then be supplied to a wing manufacture for attachment to the mainwing element 5. In this case, the movable wing tip device 6 may compriseone of the pair of hinge lugs and/or one of the pair of coupled lugs 18a.

With a different joint configuration, the movable wing tip device 6 mayrotate forwards or backwards in the plane of the wing 3 to reduce thewingspan of the aircraft, i.e., changing the sweep angle of the movablewing tip device 6, such that the movable wing tip device 6 moves neitherupwards nor downward to reduce the wing span of the aircraft. Themovable wing tip device 6 may therefore rotate in a horizontal planegenerally parallel to the length of the fuselage 2 of the aircraft 1.Moreover, any movement (horizontal and/or vertical) of the movable wingtip device 6 which varies the span of the aircraft wing 3 can be used,and corresponding mechanisms for such movement are known to the skilledperson.

When the aircraft 1 is taxiing on the ground, the wing tip actuator isactivated to rotate the movable wing tip device 6 up into the retractedposition shown in FIGS. 1 b, 3 a, 3 b. In the retracted position, thebase 20 a and remote 20 b have moved away from each other and are nolonger aligned with each other. This prevents the inductive coupler 12from inductively transmitting data and/or power when the movable wingtip device 6 is in the retracted position.

In contrast, the remote 20 b of the inductive coupler 12 is arranged tomove towards the base 20 a of the inductive coupler 12 as the movablewing tip device 6 moves to the deployed position, to allow data and/orpower to be inductively transmitted between the main wing element 5 andthe movable wing tip device 6.

FIGS. 3 a and 3 b show the movable wing tip device 6 in the retractedposition. In the retracted position, the base 20 a is exposed as shownin FIG. 3 b . When the base 20 a is exposed, it can act as a maintenancedata transfer point. A maintenance device (not shown) can comprise anexternal remote (not shown). A maintenance worker can bring the externalremote (not shown) close to the base 20 a to inductively transmit databetween the base 20 a and the external remote to run aircraftdiagnostics. Since the movable wing tip device 6 will likely beconfigured in the retracted position during on-ground maintenance, theexposed base 20 a of the inductive coupler 12 provides a convenientaccess point for running diagnostics or downloading/uploading data. Itwould be understood that the base 20 a or the remote 20 b may bepositioned in the main wing element 5 and/or movable wing tip device 6.Therefore, in the retracted position a maintenance worker may use anexternal respective base or remote to inductively transmit data betweenthe aircraft 1 and the maintenance device. In addition, since themovable wing tip device 6 may only be connected to the main wing element5 at the hinge 18 b, the moveable wing tip device 6 can be easilydisconnected from the main wing element 5 at the hinge 18 b. This allowsa maintenance worker to quickly disconnect, replace and repair themovable wing tip device 6 without cutting or disconnecting cables/wires.

The source of power may not be a single source of power from theaircraft power system (not shown) but may be multiple power sources. Thesource of data may not be a single source of data from the aircraftcontrol system (not shown), but may be multiple data sources, forexample, which provide operating instructions for different actuators,lighting systems or other devices.

FIG. 4 shows a second embodiment of the wing 3. The movable wing tipdevice 6 is in the deployed position. In this case the wing 3 comprisesfour inductive couplers 12, 32 a, 32 b, 32 c. A first electrical loop isshown comprising the inductive coupler 12, the component 16, and asecond inductive coupler 32 a. A second electrical loop is showncomprising a third inductive coupler 32 b, a second component 36, and afourth inductive coupler 32 c. A plurality of data and/or power sourcesmay be provided in order to inductively transmit data and/or poweracross the joint between the main wing element 5 and the movable wingtip device 6. Alternatively, each inductive coupler (when multipleinductive couplers are present) may be connected to a respectivecomponent similar to the example shown at FIG. 2 a . Alternatively,multiple inductive couplers can be connected in parallel to a singlecomponent in the movable wing tip device. This enables a greaterinstantaneous rate of data and/or energy transfer to/from the component.

Advantageously, each electrical loop (with or without component 16, 36)shown in FIG. 4 can be configured as a sensor to sense if the movablewing tip device 6 and the main wing element 5 are in the deployedposition. Each electrical loop formed of a first inductive coupler and asecond inductive coupler arranged in series would only be able totransmit a signal (without a certain threshold signal loss) if themovable wing tip device 6 and the main wing element 5 were in thedeployed position. Thus, the first and second inductive couplers 12, 32a are connected in series to sense if the movable wing tip device 6 isin the deployed position. This also ensures that data and/or power areonly transmitted when components are properly positioned. When themovable wing tip device 6 is in its retracted position, components onthe movable wing tip device 6 are disconnected. Therefore, components onthe movable wing tip device 6 can be automatically deactivated withoutthe use of a physical switch or connector. Thus, the components of themovable wing tip device 6 are de-powered and thus safe for a maintenanceworker to work on.

FIG. 5 shows a third embodiment of the wing 3. The main wing element 5comprises a power source 40 coupled to two inductive couplers 12, 32 d.The accumulator 16 a is coupled to both inductive couplers 12, 32 d byinput wires (not shown), and the device 16 b is coupled to theaccumulator 16 a by output wires 31.

The power transmission across a typical inductive coupler is limited.Therefore, to supply devices which have a high peak power demand (suchas a wing tip actuator or a control surface actuator) the accumulator 16a is provided in the movable wing tip device 6. The accumulator 16 areceives energy from one or both of the inductive couplers 12, 32 d andstores the energy until the energy consumer (device 16 b) requires it.The accumulator 16 a may be coupled to one or more energy consumers suchas: a wing tip actuator; a control surface actuator (e.g. for a flap,slat or aileron); a lighting arrangement; and/or any other energyconsumer.

The power system of the aircraft 1 is configured to transmit poweracross the inductive couplers 12, 32 d to the accumulator 16 a up to, orat, a first peak power level, and the accumulator 16 a is configured totransmit power to the device 16 b up to, or at, a second peak powerlevel, wherein the first peak power level is lower than the second peakpower level. In FIG. 5 , this is shown by the relative thickness of thelines (each line representing a wire 10) between the power source 40 andthe accumulator 16 a, and the thickness of the lines (each linerepresenting an output wire 31) between the accumulator 16 a and thedevice 16 b.

The accumulator 16 a may be any device suitable for storing energy, suchas a super capacitor, battery, hydraulic pump with a hydraulicaccumulator, pneumatic pump with a pneumatic accumulator, flywheel, orhydrogen fuel cell with a hydrogen tank, etc. The accumulator 16 a canbe operated to generate power from the stored energy to power the device16 b or other devices on the aircraft 1. Advantageously, a hydraulicpump with a hydraulic accumulator, can efficiently store energy ashydraulic energy and efficiently drive any hydraulic devices (such as ahydraulic actuator) within the movable wing tip device 6.Advantageously, a pneumatic pump with a pneumatic accumulator, canefficiently store energy as pneumatic energy and efficiently drive anypneumatic devices (such as a pneumatic actuator) within the movable wingtip device 6. A hydrogen fuel cell with a hydrogen tank can act as anenergy accumulator by receiving electrical energy via the inductivecoupler then operating the fuel cell to generate hydrogen using theelectrical power. Thus the hydrogen in the hydrogen tank acts as anenergy store. An embodiment may comprise multiple of the same, ordifferent, accumulator types mentioned above, for example, the movablewing tip device 6 may comprise a super capacitor and a battery.

When the accumulator 16 a is a super capacitor, a battery, a flywheel, ahydrogen fuel cell with a hydrogen tank, or any other accumulator whichreceives and transmits electrical power, then each electrical wire 10between the inductive couplers 12, 32 d and the power supply 40 (andalso each electrical input wire between the inductive couplers 12, 32 dand the accumulator 16 a) may be rated for a low electrical powerlevel/low current level. This enables the accumulator 16 a to receiveand store a constant trickle of energy. In addition, each electricaloutput wire 31 coupling the accumulator 16 a and the device 16 b may berated for a high electrical power level/high current level, to toleratean intermittent higher peak power/higher peak current when the device 16b demands power. Alternatively, all electrical wires may be rated forthe same electrical power level/current level but there may be moreelectrical wires between the accumulator 16 a and the device 16 b inorder to tolerate a higher peak power/higher peak current.

FIG. 6 shows an alternative or additional location of an inductivecoupler at the hinge line 8. The inductive coupler in FIG. 6 comprises abase 48 a and a remote 48 b, each mounted on a respective hinge lug 47a, 47 b of the hinge 18 b. Specifically, each coil of the base 48 a andthe remote 48 b is fitted to the inner face of a respective hinge lug 47a, 47 b of the hinge 18 b. A hinge pin 49 of the hinge 18 b passesthrough the lugs 47 a, 47 b and extends along the hinge line 8.

In this example, the base 48 a and remote 48 b of the inductive couplerwill always be in alignment (the axes of the base 48 a and remote 48 bcoils remain co-axial with the hinge line 8) so long as the faces of therespective hinge lugs 47 a, 47 b are coupled via the hinge pin 49. Whenthe movable wing tip device 6 is moved from a deployed position to aretracted position, the distance from the base 48 a to the remote 48 bdoes not change. The base 48 a and the remote 48 b rotate relative toeach other about the hinge line 8, such that the plane of the base 48 aand the plane of the remote 48 b remain parallel.

It is known that typical inductive couplers are not as efficient astypical electrical wires, and this inefficiency can cause a heatingeffect. Therefore, when the inductive coupler 45 is fitted into thehinge lugs 47 a, 47 b as in FIG. 6 , this can advantageously preventicing or cause de-icing at the hinge 18 b. A similar beneficial heatingeffect may also be present in the other embodiments disclosed herein.

The accumulator 16 a may be used as a store of energy which can betransmitted to the main wing element 5 if required. Thus, theaccumulator 16 a may not exclusively power energy consumers within themovable wing tip device 6, such as the device 16 b.

In FIG. 6 , the base 48 a and the remote 48 b are located at the hinge18 b, but in an alternative embodiment (not shown) the base and remoteof the inductive coupler may be mounted on the lower pair of coupledlugs 18 a. In this case the remote will move away from the base as thewing tip device 6 is rotated up to its retracted position. The heatingeffect of the inductive coupler 45 may advantageously prevent icing orcause de-icing at the lower pair of coupled lugs 18 a.

In an alternative embodiment, the movable wing tip device 6 may bereplaced by a movable semi aeroelastic wing tip device, which movesduring flight for the purpose of gust alleviation.

The wing tip actuator can be positioned in either the main wing element5 or in the movable wing tip device 6 (for instance the device 16 b maybe the wing tip actuator). If the wing tip actuator is positioned in themovable wing tip device 6, then energy from the inductive coupler orstored in the accumulator 16 a could be used to drive the wing tipactuator to move the movable wing tip device 6 between the deployedposition and retracted position. If the wing tip actuator is positionedin the movable wing tip device 6, this frees-up space at the tip end ofthe main wing element 5 for other aircraft components.

The accumulator 16 a of any embodiment may be mounted traditionally inthe leading or trailing edge areas, using known design principles, forexample, the accumulator 16 a may be mounted on the outer front face ofthe front spar, or on the outer rear face of the rear spar.Alternatively, the accumulator 16 a may be located at any of thepositions shown in FIG. 7 a or 7 b, between the front spar and the rearspar.

FIG. 7 a shows an example of the movable wing tip device 6 in a planformview in which the accumulator 16 a is in any number of accumulatorpositions 52 a-52 e. The movable wing tip device 6 shown in FIG. 7 a isa multi-spar movable wing tip device 6 with three spars 50 a-50 c (frontspar 50 c, mid-spar 50 b and rear spar 50 a).

A number of possible accumulator positions 52 a-52 e are shown betweenthe front spar 50 c and the rear spar 50 a, although it would beunderstood that only one is necessary. The accumulator 16 a may beintegrated into the multi-spar movable wing tip device 6 at any of thepossible accumulator positions 52 a-52 e. The possible accumulatorposition 52 e is in an access area with a removable manhole cover 54 foreasy access. One or more accumulators can be fitted into accumulatorpositions 52 a-52 e and each installed accumulator is connectable to aninductive coupler, and to two devices 16 b, 36 by cables/wires.

FIG. 7 b shows another example of the movable wing tip device 6 in aplanform view in which the accumulator 16 a is in any number ofaccumulator positions 52 f-52 h. The movable wing tip device 6 shown inFIG. 7 b is a multi-rib movable wing tip device 6 with two spars (rearspar 50 d and front spar 50 e) and four ribs 60 a-60 d. A number ofpossible accumulator positions 52 f-52 h are shown, between the frontspar 50 e and the rear spar 50 d, although it would be understood thatonly one is necessary. The accumulator 16 a may be integrated into themulti-rib movable wing tip device 6 between the spars and the ribs asshown in accumulator positions 52 g, 52 h, or next to a single rib asshown in accumulator position 52 f. The possible accumulator position 52h is in an access area with a removable manhole cover 64 for easyaccess. One or more accumulators can be fitted into accumulatorpositions 52 f-52 h and each installed accumulator is connectable to theinductive coupler, and to two devices 16 b, 36 by cables/wires.

If an accumulator 16 a is positioned in an access area with a removablemanhole cover 54, 64 and requires replacement or maintenance, then theaccumulator 16 a can be disconnected from its respective electricalcables/wires. This enables the accumulator 16 a to be easily accessed bya maintenance worker via the access cover to run/perform accumulatordiagnostics.

Locating the accumulator 16 a in the movable wing tip device 6 isadvantageous because its weight will counteract aerodynamic forcesacting on the wing 3, 4, which will lower the wing root bending moment(i.e. the bending moment at the inboard end of the wing 3, 4, where thewing 3, 4 meets the fuselage 2).

The movable wing tip device 6 has an inboard end and an outboard end;and a centre of gravity of the accumulator 16 a is preferably closer tothe inboard end than it is to the outboard end. Locating the centre ofgravity of the accumulator 16 a in the inboard half of the length of themovable wing tip device 6 is advantageous because i) less force isrequired to rotate the movable wing tip device 6 up, and ii) it movesthe centre of percussion closer to the centre of gravity of the aircraft1. Thus the accumulator positions 52 a, 52 b, 52 f in the inboard halfof the length of the movable wing tip device 6 are preferred.

Advantages of the use of an inductive coupler at the interface betweenthe movable wing tip device and the main wing element will be discussedgenerally here. The use of an inductive coupler removes the need to bendand flex electrical/hydraulic/pneumatic cables and connectors whichresults in improved in-service reliability. Inductive couplers are notsubject to mechanical wear and are easy to handle and maintain as thereare no moving parts in the data/power system. Moreover, less internalwing space would be needed to accommodate cable bend radii in a deployedposition, and over flexing of electrical bundles or hydraulic/pneumaticcables is also avoided when the wing is in a retracted position. Inaddition, since an inductive coupler is not 100% efficient, some localheating may occur which can help with de-icing. When moving theinductive coupler components out of the inductive communication range,the power and/or data transfer is stopped, thus some embodiments havethe ability to automatically deactivate the systems on the movable wingtip device without a physical switch connector. Finally, a movable wingtip device which is not physically wired to the main wing element is notphysically continuous at the joint. This creates an interchangeableinterface between the movable wing tip device and main wing bodyallowing an operator to quickly disconnect, replace, and repair themovable wing tip device without cutting or disconnecting cables/wires.

In other embodiments, the component 16, 36 of FIGS. 2 a to 5 may consistof an accumulator 16 a, without an additional device 16 b in the movablewing tip device 6.

Where the terms base and remote are used as components of the inductivecoupler, it is understood that these are merely labels for the twocomponents of the inductive coupler. That is, although the term “base”may typically mean a component of an inductive coupler which can sendand receive data, and only send power, in the present specification abase can also receive power. Moreover, the term “remote” may typicallymean a component of the inductive coupler which can send and receivedata, and only receive power, in the present specification a remote canalso send power. Thus, the terms “remote” and “base” may be usedinterchangeably.

Examples of suitable inductive couplers are those made by Balluff® andcan be found athttps://www.balluf.com/en-us/products/areas/A0009/groups/G0905 accessedon 4 Jan. 2022. Although, the skilled person would be able to identifyother inductive couplers.

In the embodiments above, the accumulator 16 a is configured to receivethe energy from the main wing element 5 via one or more inductivecouplers. In the embodiment of FIG. 8 the accumulator 16 a is configuredto receive the energy from the main wing element 5 via one or moreelectrical input wires 43. Thus the input wires 43 are arranged totransmit the energy from the main wing element 5 to the accumulator 16a. An advantage of using electrical input wires 43 across the wing tipjoint instead of an inductive coupler is simplicity and electricalefficiency.

In FIG. 8 the inductive couplers 12, 32 d are replaced by two electricalinput wires 43 (which can correspond to electrical wires 10) which passacross the joint and are flexible enough to enable the movable wing tipdevice 6 to move between the deployed and retracted position, with allother components being the same as in the previous embodiments.

The electrical input wires 43 are arranged to receive energy from thepower source 40, which may be housed in the main wing element or someother part of the aircraft. Whether the movable wing tip device 6 is inthe retracted position or the deployed position, the accumulator 16 a isstill connected to the power source 40 via the electrical input wires43. This allows the power source 40 to transmit energy to theaccumulator 16 a in both the retracted and deployed positions.

The accumulator 16 a of FIG. 8 is configured to receive electricalenergy via the one or more electrical input wires 43 and outputelectrical energy to the energy consumer 16 b via the one or more outputwires 31.

The use of the electrical input wires 43 to transfer electrical powerover the joint between the movable wing tip device 6 and the main wingelement 5 improves reliability compared with the use of hydraulic orpneumatic cables. Electrical input wires 43 are also typically moreflexible and easier to replace/maintain than hydraulic or pneumaticcables.

The electrical input wires 43 may be low power/low current wires whichenables them to be flexible. The device 16 b may be configured toconsume more power than the electrical input wires 43 are arranged tocarry. In other words, the energy consumer 16 b may be configured toconsume the energy from the accumulator 16 a at a higher power levelthan the power source 40 is configured to transmit to the accumulator 16a.

Each input wire 43 is rated to a first current level, each output wire31 is rated to a second current level, and the first current level islower than the second current level.

Each electrical input wire 43 may be rated for a maximum of 750V DCbecause a higher voltage may risk arcing. Each electrical input wire 43may be rated for a maximum of 2500 W because a higher power requirementwould likely require physically larger wires which could impedeflexibility. Each electrical input wire 43 may be rated for a maximum of50 A because a higher current could risk damage if the wireshort-circuited. Each electrical input wire 43 can be multi-core ortwisted core wire which aids in flexibility. Each electrical input wire43 is preferably fireproof, and is suitable for operating between −65°C. and 260° C.

In the example of FIG. 8 , electrical power is transferred across thejoint by the input wires 43 in only a single direction: from the mainwing element 5 to the accumulator 16 a. In other embodiments, electricalpower may be transferred across the joint by the wires 43 in only theopposite direction: from the accumulator 16 a in the movable wing tipdevice 6 to the main wing element 5—for example if power is generated inthe movable wing tip device 6 and the energy consumer is housed in themain wing element 6 or the fuselage 2 s. In yet further embodiments,electrical power may be transferred across the joint by the wires 43 inboth directions—both to and from the accumulator 16 a.

Where the word ‘or’ appears this is to be construed to mean ‘and/or’(unless the term “and/or” is used specifically) such that items referredto are not necessarily mutually exclusive and may be used in anyappropriate combination.

Although the invention has been described above with reference to one ormore preferred embodiments, it will be appreciated that various changesor modifications may be made without departing from the scope of theinvention as defined in the appended claims.

1. An aircraft comprising: an energy consumer; and an aircraft wing, theaircraft wing comprising: a main wing element; and a movable wing tipdevice attached to a tip end of the main wing element, wherein themovable wing tip device can move relative to the main wing element tovary a span of the aircraft wing, and the movable wing tip devicecomprises an accumulator configured to accumulate energy and output theenergy to the energy consumer.
 2. The aircraft of claim 1, wherein themovable wing tip device comprises the energy consumer.
 3. The aircraftof claim 1, wherein the accumulator is configured to receive the energyfrom the main wing element.
 4. The aircraft of claim 1, wherein themovable wing tip device comprises the energy consumer and theaccumulator is configured to receive the energy from the main wingelement.
 5. The aircraft of claim 3, further comprising one or moreinductive couplers arranged to transmit the energy from the main wingelement to the accumulator.
 6. The aircraft of claim 3, furthercomprising one or more input wires arranged to transmit the energy fromthe main wing element to the accumulator.
 7. The aircraft of claim 1,wherein the energy consumer comprises an actuator.
 8. The aircraft ofclaim 7, wherein the actuator is a wing tip actuator configured to movethe movable wing tip device relative to the main wing element to varythe span of the aircraft wing; or a control surface actuator.
 9. Theaircraft of claim 1, wherein the aircraft comprises a power sourceconfigured to transmit the energy to the accumulator, and the energyconsumer is configured to consume the energy from the accumulator at ahigher power level than the power source is configured to transmit tothe accumulator.
 10. The aircraft of claim 1, wherein the accumulatorcomprises at least one of a super capacitor, a battery, a flywheel, anda hydrogen fuel cell with a hydrogen tank.
 11. The aircraft of claim 1,further comprising one or more input wires and one or more output wiresconnected to the accumulator, wherein the accumulator is configured toreceive electrical energy via the one or more input wires and outputelectrical energy to the energy consumer via the one or more outputwires, each input wire is rated to a first current level, each outputwire is rated to a second current level, and the first current level islower than the second current level.
 12. The aircraft of claim 1,wherein the accumulator comprises a hydraulic accumulator configured tooutput hydraulic power to the energy consumer; or a pneumaticaccumulator configured to output pneumatic power to the energy consumer.13. The aircraft of claim 1, wherein the movable wing tip device has aninboard end and an outboard end; and a centre of gravity of theaccumulator is closer to the inboard end than it is to the outboard end.14. The aircraft of claim 1, wherein the movable wing tip device furthercomprises an access area with a removable cover, and the accumulator isin the access area.
 15. The aircraft of claim 1, wherein the movablewing tip device comprises a front spar and a rear spar.
 16. The aircraftof claim 15, wherein the accumulator is between the front spar and therear spar.
 17. The aircraft of claim 1, wherein the movable wing tipdevice is attached to the tip end of the main wing element by a hinge.18. The aircraft of claim 1, wherein the accumulator is configured tostore more than 0.02 kWh, 0.1 kWh or 0.5 kWh.
 19. An aircraft wingcomprising: a main wing element; and a movable wing tip device attachedto a tip end of the main wing element, the movable wing tip devicecomprising an energy consumer and an accumulator, wherein the movablewing tip device can move relative to the main wing element to vary aspan of the aircraft wing, and the accumulator is configured to receiveenergy from the main wing element, accumulate the energy, and output theenergy to the energy consumer.
 20. (canceled)
 21. A movable wing tipdevice, comprising: an accumulator configured to accumulate energy andoutput the energy to an energy consumer, and a hinge lug for attachingthe movable wing tip device to a tip end of a main wing element.